1. Field of the Invention
The invention relates to machining equipment for machining the sealing surface of the door frame in a coke oven, the machining equipment comprising: a frame, in which the machining device is movably fixed; in the machining device means for moving at least one machining unit relative to the frame in at least two directions, and in the machining unit a machine tool and its actuating means; and means for fixing the door frame and the frame of the machining device to each other while the door frame is being machined. The invention also relates to a method for machining the sealing surface of the door frame of a coke oven by means of machining equipment of the type described above, with the door frame stationary in position to act as an edge of the opening of the coke oven.
2. Description of the Related Art
In metallurgical coke production, narrow, long and high ovens are used, which are connected in parallel to form a battery of several tens of coke ovens. The operation and design of such ovens for the production of metallurgical coke are described, among other publications, in The Making, Shaping and Treating of Steel, Lankford, Samways, Craven, McGannon; Association of Iron and Steel Engineers, 1985, Tenth Edition. Each individual coke oven of the coking plant usually has a height in the range of 1.8 to 7 m, a length in the range of 9 m to 16 m, and a width in the range of 30 cm to 60 cm. The coal is charged through openings at the top and is removed by a mobile pusher one oven at a time in the battery, by pushing pushing out the finished hot charge horizontally from the oven through an open door opening at the end of each individual coke oven. The ovens are heated for instance by burning gases in flues within the walls between said narrow individual ovens, the temperature of the oven walls being approx. 1300.degree. C. At the ends of each individual oven of the battery, there are doors shaped to match the cross-section of the oven, e.g. with a length of ca. 7 m and a width of 0.7 m, and provided as covers with a lining of refractory material. The oven frame itself has a door frame, usually of cast iron, and surrounded by a precision-tooled sealing surface with a width of the order of 80 mm, the cover-like seal frame, consisting of a ca. 3-4 mm thick metal sheet, provided on the inner surface of the door, being pressed against the sealing surface. More specifically, the edge of this 3-4 mm thick seal frame is pressed like a knife against the sealing surface of the door, with the door in position in fasteners in the door frame.
The sealing surface of the door frame mentioned above will obviously wear and/or corrode in the course of time, so that the door no longer fits tightly against it. Usually the sealing surface of a new door frame has machining allowance for 1 to 3 repairs. It is well known that door frames are usually checked and overhauled at intervals of 2 to 5 years, or whenever leakage is observed. With conventional working methods, the repair of door frames is performed by removing the door while the oven is empty, but still warm, and the mouth of the oven is closed with a plugging door leaving the frame free, the frame to be repaired is removed and transported to be machined at a workshop, often situated far from the coking plant. The removed frame is replaced with a repaired replacement frame, the replacement period, i.e. the period over which the oven is empty, being from 8 to 10 hours. The work involves a great deal of installation, transport, waiting and other cost factors. In addition, the operations are onerous, given that the coke battery still is in continuous operation while being overhauled, in other words, the ovens immediately adjacent to the door frame to be serviced are still at the temperature mentioned above, approx. 1300.degree. C. This long service period of 8 to 10 hours may cause overheating and thus damage to the empty oven unit, because the adjacent ovens have to be maintained at full operating temperature as described above in order to maintain production. Long servicing periods also reduce the output of the coking plant.
Other ways of machining the door frame of a coke oven have not even been proposed before, because any ordinary machine tools, such as a movable broaching machine, would interfere with the operation of the other ovens in the battery, and especially that of the pusher emptying the ovens. On the other hand, manual tools, such as a corner grinder, do not provide adequate precision for the sealing surface, and moreover, such operations are hampered by awkward working positions, hot circumstances, as mentioned above, while time exposed to weather conditions at the same time.